As global populations age, there is a growing need for reliable, valid and comparable information on the health of older adults. Meaningful comparisons are needed within countries to characterize sub-national differences, quantify health inequalities, and target programs to those with the greatest need;comparisons are also needed across countries to set goals and chart progress in improving population health. While self-reports on functional health and disability offer a relatively low-cost option for data collection in surveys, these measures elude simple interpretation because survey response scales may be interpreted differently by different respondents: what one person calls "mild" difficulty in moving around, another might call "moderate" or "severe" difficulty because of varying norms, expectations, or reference points. This variation in interpretation and use of response scales is referred to as "response category cut-point shift." The overall goal of this project is to assess the comparability of self-reports on functional health based on secondary analysis of survey data that include measured performance tests and anchoring vignettes on several health dimensions. Performance measures and vignettes both provide concrete scale anchors to reveal response category cut-point shifts, which enables adjustment of self-reports to better distinguish real differences in health from differences in expectations or survey response styles. This proposal on "Comparability of self-reports on functional health" has two specific aims: 1. Examine response category cut-point shifts across population subgroups in the United States, in self- assessments of physical function, vision, hearing and cognition, using performance-based measures in NHANES 1999-2006. 2. Examine response category cut-point shifts across countries in Europe, in self-assessments of mobility and cognition, using panel data on both performance-based measures and anchoring vignettes in the SHARE study. Together, the two study aims draw on a common analytic framework to confront questions of comparability both within and across settings, deploying two major strategies for enhancing comparability of self-reports in a way that enables hypothesis testing and comparative evaluation of the strategies. We expect that the proposed project will help advance the methodological basis for understanding functional health in aging global populations, and for improved measurement and interpretation of self-reported health indicators. PUBLIC HEALTH RELEVANCE: Reliable, valid and comparable information on health is critical to understanding returns on investments in medicine and public health, making resource allocation decisions, and evaluating the impact of interventions and policies. Simple, self-reported questions on functioning and disability may be administered in surveys at relatively low cost but may produce results that are difficult to interpret because they are not comparable across individuals and communities. This project aims to advance strategies for improving comparability of self-reported measures and thereby enhancing the value of these measures for public health monitoring and practice.